Taking communion called a sin

I hope someone will gently educate Dan Goldberg and tell him that taking communion as a gesture of reciprocity to a friend is not an appropriate way of showing friendship.

Although his attitude about hearing any criticism about his gesture seems strident and arrogant, hopefully someone who is knowledgeable and whom he trusts will be able to get through to him that taking communion, davka on Shabbat (that’s when Christmas fell) is — yes, I’ll say it — a sin. And it certainly doesn’t lend evidence to his protestation that he is a traditional Jew.